By George Hart for the Museum of Mathematics


Two years ago, we looked at some constructions made from playing cards that are slotted and slid together. Here is a new one, by Zach Abel.

Thirty cards are required, and each is slotted as in the template below. To build your own, simply copy this pattern onto thirty cards, cut on the red lines, and assemble as in the image. Note that Zach’s version above has some cards facing in and some facing out, however, the template must always face the same way. So if you want some cards to face differently, turn them over before coping the template on them.

Notice how sets of five cards meet at their short edges form six different prism-like “equators.” The construction approximates the uniform compound of six pentagonal prisms, but with rectangular sides instead of squares.

See all of George Hart’s Math Monday columns

Gareth Branwyn

Gareth Branwyn

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy person’s memoir,” called Borg Like Me.

  • Harun Sut
  • Frederick Koh

    Now this is brilliant. Peace.

  • Lindsay Manahan

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    couldnt do this at all, can you post some furhter tutorial ?

    • davad

      Looks like you need to start with three sets of two (6) cards …. then it gets fuzzy. Can’t figure out how the 5 of these sets get merged to form the globe. A more details tutorial would be great.

  • Josh

    please post a video of someone making the ball of cards- it looks very complicated and I dont know how to assemble it!

  • davad

    Please…. someone post a tutorial on this one. At least a version that has all the cards the same way. I think that would help.